The present invention relates to an optical communication card having multiple functions and to a communication device.
The recent widespread use of the optical communication technology in various fields, such as the Internet and optical phones, requires an optical transmission system to have an extended, long transmission path and a large-capacity transmission capability. A variety of optical communication cards are required to implement these requirements.
In general, the optical switch function, capable of directly path-switching a large capacity of optical signals, is efficient on a transmission line. In a long-distance transmission system, the longer the propagation distance becomes, the more data errors are generated during signal propagation. To solve this problem, the error correction function, called the FEC (Forward error correction) function, is provided to allow the receiving side to correct data without retransmitting the data even if a data error is generated, thereby implementing optical transmission in a long-distance communication.
An increase in the transmission capacity is implemented by the multiplexing technology such as a time-division multiplexing device or a wavelength-division multiplexing device and, today, an optical transmission system having the transmission capacity of 40 Gbps or 100 Gbps has been developed. However, a time-division multiplexing device and a wavelength-division multiplexing device are installed independently and so there is a need for a layer integration device having various functions for reducing the capital investment.
In general, the layer integration device described above comprises a transponder card having the function to connect to an opposed device, the wavelength conversion function, and the FEC function; and a wavelength multiplexing card having the wavelength multiplexing function. The layer integration device further comprises a switch card having the de-multiplexing function necessary for a time-division multiplexing device; and an interface card connected to the switch card and to the opposed device. In the conventional configuration, the signal accepted by the interface card is transmitted to the switch card and is de-multiplexed by the switch card and, after being cross-connected, the signal is multiplexed again and is transmitted to another interface card. This configuration requires many types of communication cards. For example, JP-A-2006-166037 describes the configuration in which there is an optical switch circuit between the optical transmitter/receiver and multiple transponders and, in addition, multiple cards are required according to a difference in the switching method. In addition, such a configuration requires a communication carrier to provide a redundant configuration to avoid an interruption in the data transmission. To solve this problem, device duplication, or card configuration duplication described in JP-A-2006-41921, is employed to implement a redundant configuration in both the client side (user side) and the line side (provider side).